https://github.com/loglayer/loglayer
A modern logging library for Javascript / Typescript that routes logs to various logging libraries, cloud providers, files, StatsD, and OpenTelemetry while providing a fluent API for specifying log messages, metadata and errors.
https://github.com/loglayer/loglayer
abstraction bun datadog deno electron file-rotation javascript log log-rotation logger logging logging-library nextjs nodejs opentelemetry pino statsd structured-logging typescript wrapper
Last synced: 4 days ago
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A modern logging library for Javascript / Typescript that routes logs to various logging libraries, cloud providers, files, StatsD, and OpenTelemetry while providing a fluent API for specifying log messages, metadata and errors.
- Host: GitHub
- URL: https://github.com/loglayer/loglayer
- Owner: loglayer
- License: mit
- Created: 2021-11-25T23:24:36.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2026-02-17T06:11:14.000Z (22 days ago)
- Last Synced: 2026-02-17T09:48:52.007Z (22 days ago)
- Topics: abstraction, bun, datadog, deno, electron, file-rotation, javascript, log, log-rotation, logger, logging, logging-library, nextjs, nodejs, opentelemetry, pino, statsd, structured-logging, typescript, wrapper
- Language: TypeScript
- Homepage: http://loglayer.dev/
- Size: 9.65 MB
- Stars: 422
- Watchers: 3
- Forks: 7
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Agents: AGENTS.md
Awesome Lists containing this project
README
# LogLayer
`loglayer` is a unified logger that routes logs to various logging libraries, cloud providers, files, and OpenTelemetry while providing a fluent API for specifying log messages, metadata and errors.
Supports browser, Node.js, Bun, and Deno platforms.
For full documentation, read the [docs](https://loglayer.dev).
```javascript
// Example using the Pino logging library with LogLayer
// You can also start out with a console logger and swap to another later!
import { LogLayer } from 'loglayer';
import { pino } from 'pino';
import { PinoTransport } from '@loglayer/transport-pino';
import { redactionPlugin } from '@loglayer/plugin-redaction';
const log = new LogLayer({
// Multiple loggers can also be used at the same time.
transport: new PinoTransport({
logger: pino()
}),
// Plugins modify log data before it's shipped to your logging library.
plugins: [
redactionPlugin({
paths: ['password'],
censor: '[REDACTED]',
}),
],
// Put context data in a specific field (default is flattened)
contextFieldName: 'context',
// Put metadata in a specific field (default is flattened)
metadataFieldName: 'metadata',
})
// persisted data that is always included in logs
log.withContext({
path: "/",
reqId: "1234"
})
log.withPrefix("[my-app]")
.withError(new Error('test'))
// data that is included for this log entry only
.withMetadata({ some: 'data', password: 'my-pass' })
// Non-object data only (numbers, booleans, and strings only)
// this can be omitted to just log an object / error
// by using .errorOnly() / .metadataOnly() instead of withError() / withMetadata()
.info('my message')
```
```json5
{
"level": 30,
"time": 1735857465669,
"msg": "[my-app] my message",
"context": {
"path": "/",
"reqId": "1234",
},
"metadata": {
"password": "[REDACTED]",
"some": "data",
},
"err":{
"type": "Error",
"message": "test",
"stack": "Error: test\n ..."
}
}
```
With the [Pretty Terminal Transport](https://loglayer.dev/transports/pretty-terminal):
The [Hot Shots Mixin](https://loglayer.dev/mixins/hot-shots) adds a metrics API to LogLayer:
```typescript
import { LogLayer, useLogLayerMixin, ConsoleTransport } from 'loglayer';
import { StatsD } from 'hot-shots';
import { hotshotsMixin } from '@loglayer/mixin-hot-shots';
// Create a StatsD client
const statsd = new StatsD({
host: 'localhost',
port: 8125
});
// Register the mixin (must be called before creating LogLayer instances)
useLogLayerMixin(hotshotsMixin(statsd));
// Create LogLayer instance
const log = new LogLayer({
transport: new ConsoleTransport({
logger: console
})
});
// Use StatsD methods through the stats property
log.stats.increment('request.count').send();
log.info('Request received');
log.stats.timing('request.duration', 150).send();
log.info('Request processed');
log.stats.gauge('active.connections', 42).send();
log.info('Connection established');
```
## Development Setup
This is a monorepo using [`pnpm`](https://pnpm.io/installation) for package management and [`turbo`](https://turbo.build/repo/docs/getting-started/installation) for build orchestration.
If you're looking to contribute or work with the source code, follow these steps:
1. Clone the repository
2. Install dependencies:
```bash
pnpm install
```
3. Install git hooks:
```bash
pnpx lefthook install
```
4. Build all packages:
```bash
turbo build
```
## Running Tests
To run tests for all packages, use the following command:
```bash
turbo test
```
## Linting and Formatting
This project uses [Biome](https://biomejs.dev/) for linting and formatting. To run lint and format across all packages:
```bash
turbo lint
```
To run lint only on staged files (used by git hooks):
```bash
turbo lint:staged
```
## Viewing docs
The docs use [vitepress](https://vitepress.dev/). To view the docs locally, run:
```bash
pnpm run docs
```
To check that docs build correctly and are ready for production:
```bash
pnpm run docs:build
```
## Project Structure
```
loglayer/
├── docs/ # Documentation (vitepress)
├── packages/
│ ├── core/ # Core packages
│ │ ├── context-manager/ # Context manager system core
│ │ ├── log-level-manager/ # Log level manager system core
│ │ ├── loglayer/ # Main LogLayer implementation
│ │ ├── plugin/ # Plugin system core
│ │ ├── transport/ # Transport system core
│ │ ├── shared/ # Shared utilities and types
│ │ └── tsconfig/ # Shared TypeScript configurations
│ ├── context-managers/ # Official context manager implementations
│ ├── log-level-managers/ # Official log level manager implementations
│ ├── transports/ # Official transport implementations
│ ├── mixins/ # Official mixins implementations
│ ├── plugins/ # Official plugins
│ └── integrations/ # Framework integrations (e.g. ElysiaJS)
```
## Documentation
For detailed documentation, visit [https://loglayer.dev](https://loglayer.dev)
## Contributing
We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.
Made with ❤️ by [Theo Gravity](https://suteki.nu). Logo by [Akshaya Madhavan](https://www.linkedin.com/in/akshaya-madhavan).